This invention concerns low-profile sheathing for encasing and protecting elongated items, such as electrical wiring, which is routed within the passenger compartment or trunk of an automobile.
Electrical wiring is used extensively in automotive applications where it is routed through the various compartments of the car, such as the passenger compartment, the trunk or along the inside of the roof, to provide electrical power to lights, radios, speakers or other electrical or electronic components within the automobile. It is advantageous to encase elongated items such as wiring within a sheath which organizes and protects the wiring. Organizing the wiring is accomplished by capturing and grouping the various wires within one or more sheaths. This avoids an unsightly tangle of wires within the automobile which can be inadvertently snagged and possibly severed or disengaged from a terminal. Organizing the wiring also allows for rapid identification of the wires, thereby providing for efficient troubleshooting and repair. These are desirable characteristics as automotive electrical system problems tend to be difficult to diagnose and time consuming to repair.
Protection of the wiring is also desirable to prevent physical damage to both the wiring and its insulation due to abrasion and pinching. Abrasion of the wiring may be caused by vibration of the car structure due to rough engine operation and road roughness. The wiring responds to the vibration and rubs against a nearby portion of the chassis. Abrasion, as well as pinching, may be caused by physical contact of the wiring with passengers as they enter or exit the vehicle or cargo as it is placed in the trunk. Pinching of a wire, for example, between a sharp edge on the chassis and the foot of a passenger can sever a wire, and abrasion of the wire by repeated rubbing motion against the chassis can cause a short circuit by wearing the insulation away and allowing the bare wire to contact a metal part of the chassis which is typically at negative electrical potential. Short circuits in the electrical system of an automobile usually lead to equipment failure can cause a dead battery and may result in a serious fire.
In order to allow the wiring to pass within the various compartments of the automobile, it is desired that the protective sheathing have a low profile, i.e., be substantially flat so as to fit unobtrusively between carpeting and the floor or side panel within the passenger compartment or trunk or between the roof and the roof lining. The sheathing should also be substantially stiff in a direction transverse to its width so as to be able to effectively capture and hold the wiring in place in a substantially flat configuration. At the same time, the sheathing should be relatively flexible transverse to its length so as to bend readily and follow contours of the automobile chassis.
Protective sheathing for elongated items should also be economical to produce, easy to incorporate into an existing layout or design and have reliable means for sealing and unsealing the sheathing so that it can readily receive wiring and then securely capture and protect it.
The invention concerns a sheath for receiving and protecting elongated items. The sheath comprises first and second elongated substrates, each having opposite edges defining a width of each substrate. The edges of one substrate are paired with the edges of the other substrate. One of the pairs of edges is flexibly joined lengthwise of the substrates to form a hinge. The hinge is pivotally movable between an open position, wherein the first and second substrates are angularly oriented with respect to one another, and a closed position, wherein the first and second substrates are overlying one another in substantially parallel relationship. The sheath has means for securing the first and second substrates in the closed position mounted along the other pair of edges opposite to the hinge. The elongated items are received between the substrates when the substrates are in the open position and captured between the substrates when they are in the closed position. Corrugations are formed in the substrates transversely to the width to provide increased bending stiffness about the long axis of the sheath while simultaneously providing bending flexibility perpendicular to the long axis.
Preferably, the first and second substrates are integrally formed from a single sheet of material, such as a thermoplastic which is heat formable into a desired shape. The hinge may comprise a substantially continuous region of the sheet having reduced thickness and positioned between and thereby defining one of the edges of the first and second substrates. The reduced thickness region provides flexibility allowing the hinge to bend easily between the open and closed positions.
Preferably, the hinge is formed by a plurality of first regions of the sheet having reduced thickness. The first regions of reduced thickness are oriented to be substantially within the plane of the sheet forming the hinge. The hinge further includes a plurality of second regions of the sheet also having reduced thickness. The second regions of reduced thickness are oriented substantially perpendicularly to the plane of the sheet and are connected to the first and second substrates by respective connecting portions of the sheet. Each of the connecting portions are bent through a substantially right angle, one right angle connecting portion being positioned on either side of each of the second regions of reduced thickness. The first and second regions of reduced thickness are positioned one behind the other in an alternating pattern lengthwise along the substrates.
The invention further includes an apparatus for forming the flexible hinge between two substrates described above. The hinge and the substrates comprise a flexible sheet material, such as a thermoplastic, which is formable into a predetermined shape when heated and which holds the shape upon cooling. The apparatus comprises a first gear having gear teeth and being rotatable about a first axis, a second gear having gear teeth and being rotatable about a second axis arranged in a substantially parallel, spaced relation to the first axis such that the gear teeth on the first and second gears intermesh. The apparatus also includes a third gear having gear teeth and being rotatable about the first axis in fixed relation with the first gear. The third gear is positioned adjacent to the first gear. A fourth gear having gear teeth is rotatable about the second axis in fixed relation with the second gear. The gear teeth on the fourth gear intermesh with the gear teeth on the third gear, and the fourth gear is positioned adjacent to the second gear.
The gear teeth on the first and fourth gears each have respective beveled faces which move into and out of overlapping alignment with one another upon rotation of the gears. Each of the beveled faces are separated by a first gap when aligned. The sheet material, when heated, is fed between the intermeshing teeth of the first, second, third and fourth gears and is thereby deformed to comply with the shape of the gear teeth. The beveled faces of the first and the fourth gears form a plurality of first regions of reduced thickness at spaced intervals along the sheet material as the sheet material passes through the first gap. The first regions of reduced thickness define the hinge and divide the sheet material into the substrates.
The gear teeth on the second and third gears each have respective side surfaces which move into and out of overlapping alignment with one another upon rotation of the gears. The side surfaces are separated from one another by a second gap. The gear teeth on the second and third gears each have radially outwardly facing surfaces offset from one another. The sheet material, when heated and fed between the intermeshing gear teeth as described above, passes through the gap between the side surfaces of the second and third gears, thereby forming a plurality of second regions of reduced thickness at spaced intervals along the sheet material. The second regions of reduced thickness are interspersed between the first regions of reduced thickness. The facing surfaces and the teeth of the second and third gears intermesh with the first and second gears and bend the sheet material through a first and a second substantially right angle bend thereby orienting the second regions of reduced thickness substantially perpendicularly to the sheet material. Together with the first regions of reduced thickness, the second regions of reduced thickness also define the hinge and divide the sheet material into the substrates.
The invention further includes a method of forming a flexible hinge comprising a plurality of first and second regions of reduced thickness as described above. The method comprises the steps of:
(A) providing a flexible sheet comprising a material which is formable into a predetermined shape when heated to a predetermined temperature and which holds the shape upon cooling;
(B) heating the sheet material to the predetermined temperature;
(C) forming a plurality of first regions of reduced thickness at spaced intervals along the sheet material, the first regions being positioned substantially in the plane of the sheet material;
(D) forming a plurality of second regions of reduced thickness at spaced intervals along the sheet material, the second regions being interspersed between the first regions and being oriented substantially perpendicularly to the plane of the sheet material;
(E) bending the sheet material through a first and a second substantially right angle bend on either side of each of the second regions of reduced thickness; and
(F) cooling the sheet material to fix the first and the second regions of reduced thickness and the right angle bends, the first and second regions defining the hinge.
It is an object of the invention to provide a low-profile sheath for protecting elongated items.
It is another object of the invention to provide a low-profile sheath having stiffening corrugations.
It is another object of the invention to provide a low-profile sheath having a hinge.
It is another object of the invention to provide a hinge which compensates for the difference in shear stiffness between the hinged edge and free edges of the sheath.
It is still another object of the invention to provide an apparatus for manufacturing a low-profile sheath.
It is yet another object of the invention to provide an apparatus for manufacturing a hinge usable with the low-profile sheath.
These and other objects of the invention will become apparent upon consideration of the following drawings and detailed description of the preferred embodiments.